The present invention relates to a filter insert and a method for producing a filter insert comprising a filter medium folded in an accordion-type shape, in which the bent edges are first impressed in a first operating step. At least two glue beads are applied to the surface of the filter medium by glue application devices which are provided with glue application nozzles, and the folding is subsequently carried out.
From German Patent Document DE-AS 12 99 534, a filter insert is known which is made of folded filter material. This filter insert has a glue mass which extends transversely to the fold edges and is connected with the filter material. This glue mass is used as a spacer.
Known filters of this type for motor vehicle engines also use glue masses or glue beads as spacers. These glue beads are also applied without interruption to the sides of the filter medium during the production. During an accordion-type folding of the filter medium, these glue beads form the lateral sealing of the filter insert.
A filter insert of this type is manufactured, for example, by the firm FILTERWERK MANN+HUMMEL GMBH and is sold under the designation C 34 109/1. These so-called "rectangular" filters are expedient where installation conditions permit such a filter. Rectangular filters are available in various dimensions and filtering capacities.
As a result of the progressive development in automobile construction in the endeavor to obtain compact vehicles, there is less available space for an air filter in the engine compartment of a vehicle. The space is often not sufficient for a conventional rectangular cartridge so that sometimes two filters or two cartridges are arranged at different points.